This invention relates to positioning systems and, more particularly, to an improved single cycle positioning system which utilizes a DC motor to accurately position a cyclicly movable member at a precise location within its movement cycle.
There are numerous machines where a member is cyclicly driven and it is required to stop the member at a precise location within its positional cycle. One such type of machine is a crimping press which is utilized repetitively to attach electrical terminals to the ends of wires. U.S. Pat. No. 3,343,398 discloses one such machine wherein a ram is coupled to a shaft and, during each single revolution of the shaft, the ram is moved downwardly and then back to its initial position thereby to move a crimping die on the end of the ram into engagement with a terminal. The shaft is coupled through a single revolution clutch to a flywheel which is continuously driven by a continuously operated motor. When it is desired to crimp a terminal onto a wire, the single revolution clutch is engaged to drive the shaft through a single revolution so that the ram is moved through its cycle.
While the aforedescribed arrangement is effective for its intended purpose, it suffers from a number of disadvantages. Thus, for example, the continuous running of the motor is wasteful of electrical energy and results in the generation of heat. Also, the use of a single revolution clutch causes noise and vibration. Further, the clutch has to be properly maintained and worn parts replaced.
U.S. Pat. No. 5,449,990, discloses a single cycle positioning system which substitutes electronic control of an induction motor for a single revolution clutch. While effective and well received in the industry, the electronic control system for operating the induction motor is relatively expensive. It would therefore be desirable to provide a lower cost single cycle positioning system of the type described.